The present disclosure relates to improved photoreceptor designs for electrostatographic printing devices, particularly photoreceptors having hydrolyzed semi-conductive nanoparticles incorporated into an undercoating layer. More particularly, the present disclosure relates to photoreceptors having an undercoating layer that includes hydrolyzed semi-conductive nanoparticles of metal alkoxide and an amine.
In electrophotography, an electrophotographic substrate containing a photoconductive insulating layer on a conductive layer is imaged by first uniformly electrostatically charging a surface of the substrate. The substrate is then exposed to a pattern of activating electromagnetic radiation, such as, for example, light. The light or other electromagnetic radiation selectively dissipates the charge in illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image in non-illuminated areas of the photoconductive insulating layer. This electrostatic latent image is then developed to form a visible image by depositing finely divided electroscopic marking particles on the surface of the photoconductive insulating layer. The resulting visible image is then transferred from the electrophotographic substrate to a necessary member, such as, for example, an intermediate transfer member or a print substrate, such as paper. This image developing process can be repeated as many times as necessary with reusable photoconductive insulating layers.
Electrophotographic imaging members (i.e. photoreceptors) are well known. Electrophotographic imaging members are commonly used in electrophotographic (xerographic) processes having either a flexible belt or a rigid drum configuration. These electrophotographic imaging members sometimes comprise a photoconductive layer including a single layer or composite layers. These electrophotographic imaging members take many different forms. For example, layered photoresponsive imaging members are known in the art. U.S. Pat. No. 4,265,990 describes a layered photoreceptor having separate charge generating and charge transport layers. The charge generating layer disclosed in the 990 patent is capable of charge generating holes and injecting the photogenerated holes into the charge transport layer. Thus, in the photoreceptors of the 990 patent, the charge generating material generates electrons and holes when subjected to light.
More advanced photoconductive photoreceptors containing highly specialized component layers are also known. For example, a multilayered photoreceptor employed in electrophotographic imaging systems sometimes includes one or more of a substrate, an undercoating layer, an intermediate layer, an optional hole or charge blocking layer, a charge generating layer (including a charge generating material in a binder) over an undercoating layer and/or a blocking layer, and a charge transport layer (including a charge transport material in a binder). Additional layers such as one or more overcoating layer or layers are also sometimes included.
U.S. Pat. No. 5,958,638 discloses some known materials used for undercoating layers. Materials known to be usable in intermediate and undercoating layers include a resin material alone, such as polyethylene, polypropylene, polystyrene, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane, epoxy resin, polyester, melamine resin, silicone resin, polyvinyl butyryl, polyamide and copolymers containing two or more of repeated units of these resins. Such resin materials also include casein, gelatin, polyvinyl alcohol, ethyl cellulose, etc. Intermediate and undercoating layers are typically formed by a proper coating technique, like dip coating process, such as the methods disclosed in, for example, U.S. Pat. Nos. 5,958,638 and 5,891,594.
U.S. Pat. No. 6,277,535 discloses alternative materials used for undercoating layers. The patent discloses that the undercoating layer can include materials derived from the reaction of a silyl-functionalyzed polymer with a first silane coupling agent and an optional second silane coupling agent. The material is described to provide a mechanically and electrically robust undercoating layer.
U.S. Pat. No. 5,789,127 discloses an electrophotographic photoreceptor comprising an electrically-conductive substrate having provided thereon an undercoat layer and a photoconductive layer. The undercoat layer is formed by using a high molecular weight compound having an alkoxysilyl group; a high molecular weight compound having an alkoxysilyl group and an organic metal compound; or a high molecular weight compound having an alkoxysilyl group, an organic metal compound and a silane coupling agent. As the organic metal compound there may be preferably used at least one selected from the group consisting of an organic zirconium compound and an organic titanium compound.
U.S. Pat. No. 6,261,729 discloses a photoreceptor including: a substrate, a charge blocking layer including n-type particles and a linear phenolic binder composition, and an imaging layer. The n-type particles of the blocking layer can be, for example, metal oxide particles such as needle shaped titanium dioxide particles or grain shaped titanium dioxide particles.